The function atoi () in C

The int atoi function (const char * str) in standard C library converts a string pointed to by parameter str to an integer (int type).

Declare atoi () function in C

Below is the declaration for the atoi () function in C:

 int atoi ( const char * str ) 

Parameters

str - This is a string representing an integer.

Returns the value

This function returns an integer that has been converted as an int value. If no valid conversion is performed, the function returns 0.

For example

The following program C illustrates the usage of the atoi () function in C:

 #include #include #include int main () { int val ; char str [ 20 ]; strcpy ( str , "98993489" ); val = atoi ( str ); printf ( "Gia tri duoi dang chuoi = %s, nGia tri duoi dang so nguyen = %dn" , str , val ); strcpy ( str , "QTM.com" ); val = atoi ( str ); printf ( "nGia tri duoi dang chuoi = %s, nGia tri duoi dang so nguyen = %dn" , str , val ); return ( 0 ); } 

Compile and run the above C program to see the results.

According to Tutorialspoint

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