1. Character String Manipulation

2. Overview Character string functions sscanf() function sprintf() function

3. Some Character String Functions double atof(const char *string); - Converts string into a floating point value int atoi(const char *string); - Converts string into an int value char *strcat(char *s1, const char *s2); - Appends s2 onto the end of s1 char *strchr(const char *s, int c); - Searches for first occurrence of c in s int strcmp(const char *s1, const char *s2); - Compares s1 to s2 char *strcpy(char *s1, const char *s2); - Copies s2 onto s1 size_t strlen(const char *s); - Returns the number of characters in s char *strstr(const char *s1, const char *s2); - Searches for s2 in s1 char *strtok(char *s1, const char *s2); - Extracts tokens from string s1 based on token separators in s2

4. sscanf() Function #include int sscanf(const char *buffer, const char *format, …); The sscanf() function is identical to scanf() except that data is read from the array pointed to by buffer rather than stdin The return value is equal to the number of variables that were actually assigned values –A value of zero means that no fields were assigned any values

5. sprintf() Function #include int sprintf(char *buffer, const char *format, …); The sprintf() function is identical to printf() except that the output is put into the array pointed to by buffer instead of being written to stdout The array pointed to by buffer should be null terminated The return value is equal to the number of characters actually placed into the array The sprintf() function provides no bounds checking on the array pointed to by buffer

6. Example use of strcpy(), sscanf() and sprintf() #include #define MAX_LENGTH 50 int main(void) { char stringA[MAX_LENGTH]"; char stringB[MAX_LENGTH]; int count; float costPerItem; int binNbr; char name[MAX_LENGTH]; float totalCost; (More on next slide)

7. Example use strcpy(), sscanf() and sprintf() strcpy(stringA, "103 67.4 35bottle“); sscanf(stringA, "%d %f %d%s", &count, &costPerItem, &binNbr, name); fprintf(stderr, "Input data: %d %.2f %d %s\n\n", count, costPerItem, binNbr, name); totalCost = count * costPerItem; sprintf(stringB, "%d %s items * $ %.2f per %s = $ %.2f", count, name, costPerItem, name, totalCost); printf("Computation for Bin # %d:\n %s\n", binNbr, stringB); return 0; } // End main

8. Sample output Input data: 103 67.40 35 bottle Computation for Bin # 35: 103 bottle items * $ 67.40 per bottle = $ 6942.20