How can I write a program in c which invert a string in a function like this, Count, 3,man will be coumannt?

Do you want to invert or insert? The example you have provided has the string "man" inserted at index 3 in the string "Count". Also, the C in the input has been converted to c in the output i.e. uppercase to lowercase conversion. Insert_and_change_case(input string, index at which insertion will happen, string to be inserted){ make new empty string with length which will be the sum of both input srtings; read less

By what I understand from your question is that you want to insert the second string (“man” in this case) after the given/specified position into the first string. (I’m assuming that the ‘C’ and ‘c’ means the same and makes no difference to what you seek) The following is the code #include "iostream.h" void stringProcessing(char a[], int pos, char b[]); int main() { char c[100]={"count"}; char x[100]= {"man"}; int n=3; stringProcessing(c,n,x); } void stringProcessing(char a[], int pos, char b[]) { //initialize required stuff int i=0,j=0; int sizeOfB=0, sizeOfA=0; //find size of A and B for(i=0; a[i]!='\0'; i++) sizeOfA++; for(i=0; b[i]!='\0'; i++) sizeOfB++; //Shift right elements in A by the size of B for(i=sizeOfA+sizeOfB,j=sizeOfA; i>pos; i--) a[i]=a[j--]; //insert B in A for(i = pos,j=0; jread less