C++

C++ Error: No Matching Function for Call

No matching function for call means when we are calling some certain functions, but the id of that function is not matching the argument of the function that is defined. Hence we obtain an error ‘no matching function for a call’ to C++. Whenever the compiler states there are no matching methods, it generally indicates the compiler identified a method by the identical name like we had given the parameters to the function.

So when we continue to pass the specified method of the incorrect type or the inappropriate set of parameters to the function. A function definition specifies the name of the method to the compiler as well as how to invoke it. The function’s entire content is being declared explicitly. In this article, we will talk about how the error ‘No matching function for a call’ appears in C++.

Use Object of the Class

In this scenario, the function parameter is not matching during the call, so we will try to pass pointers where references are needed and use different class reference types in function calls. Whenever we invoke the function but the function definition of the argument is not being matched, then the error ‘No matching function for call to C++’ is raised.

Now we have to fix the error; for this purpose, we just provide the suitable matching parameter during the definition of the function. The code, along with its detailed description, can be seen underneath.

At the start of the code, we are going to include the library <iostream>, which is used for input and output functionalities. We also utilize a standard namespace. Then we initialized the class with the name of ‘A,’ and we specified the function setValue() public. We are passing the parameter of value with the data type of integer to this function. We also initialized a variable ‘value’ of the class that has an integer data type.

In the next line, we invoke another function setValue(). This method holds the variable ‘value’ as its argument. We do increment in the value that was passed as its arguments. Then we call the main() function, and we are given ‘argc’ having integer data type and ‘argv’ pointer of character data type as its arguments. The ‘argc’ is the no. of parameters that are provided in the code from the operating system. The ‘argv’ is the collection of parameters.

Now we create an object ‘obj’ of the class ‘A.’ We invoke the method setValue() function. The ‘obj’ is passed as its arguments. But we did not connect the object with the class. That is why when we call the function setValue(), it returns an error because we do not have that class where we invoke the setValue() function. In the above code, we are passing a class object within the setValue() function calling argument, but if we check in the setValue() function definition, we assume the passing argument value as an integer. To terminate the code, we utilized the ‘return 0’ command. Here the output of the above-stated code can be verified.

We obtain the error ‘no matching function for call to A’ after executing the above-mentioned code.

How to Resolve This Error?

To fix this error during the method call, we must provide adequate corresponding parameters to the function. The other way of resolving this error is to make different overloaded functions have different parameters. Here we just modify the argument of the function main(). Thus ‘no matching function for the call’ to C++ error would be removed. The code, along with its detailed description, can be seen underneath.

After using the standard namespace, we introduce the header file <iostream>. We constructed a class named ‘A’ and made its function setValue() public. This function receives the variable ‘value’ as a parameter, which has the data type integer. We also initialized an integer data type variable called ‘value’ in the class. This variable is also set public. The next line calls another function called setValue(). The variable ‘value’ having the data type integer is provided as a parameter in this function. We increase the value that was supplied as one of the inputs.

In the next step, we invoke the main() method. Within the main() function, we will provide ‘argc’ of integer data type and ‘argv’ of character data type as its arguments. The ‘argc’ shows the number of parameters provided by the operating system in the program. The ‘argv’ is a parameter collection. Now we’ll make an object of the class ‘A’ termed ‘obj.’ We initialized the variable ‘value’ with the integer data type. We have utilized the setValue() method of the object and set the ‘value’ as parameters of this function.

In the end, we add ‘return 0’ to close the program. Remember that we must enter the same data types of the functions and their arguments in the main() function. Then we have passed that function to its object and returned it. Here the output of the above-stated code can be verified.

Conclusion

In this article, we have explored the reasons for getting the error ‘no matching function for a call’ and how to resolve this. Whenever we receive this error, then we have to check the parameters of the required methods as well as their data type. We make mistakes while providing the arguments to the function arguments. We mismatch the parameters to the function. We might be required to give the matched parameter to the specified method. Or we have to add a new function with the same data type. After checking and adding suitable parameters to the function in the program, the error, ‘no matching function for a call’ will be resolved.

About the author

Kalsoom Bibi

Hello, I am a freelance writer and usually write for Linux and other technology related content