c - Why is an int resetting to zero after each iteration of for loop? -

as title says, have simple loop cumulative variable += value of calculation. however, after each iteration, variable being reset zero. why?

here's loop:

int score_board(board* b) {     int i;     int total_score = 0;      for(i = 0; < 4; i++)     {         printf("current total = %d\n",total_score);         total_score += score_line(grab_line(b, i, 0));         total_score += score_line(grab_line(b, i, 1));         printf("scored row , columnn %d\tcum total=%d\n", i, total_score);     }      return total_score; } 

and here's output i'm getting, proving while total_score set value want during 1 iteration, loses value upon resetting loop:

current total = 0 line score = 11000 line score = 40000 scored row , columnn 0        cum total=51000 current total = 0 line score = 60000 line score = 50000 scored row , columnn 1        cum total=110000 current total = 0 line score = 20000 line score = 40000 scored row , columnn 2        cum total=60000 current total = 0 line score = 50000 line score = 50000 scored row , columnn 3        cum total=100000 

edit: found it! inside of score_line, int return wasn't initialized zero. rookie mistake.

thanks all.

[to "long" comment]

temporarily comment out calls score_line , grab_line , replace them integers...

total_score += 42; // score_line(grab_line(b, i, 0)); total_score += 42; // score_line(grab_line(b, i, 1)); 

and see if same results, if don't re-enable 1 of score_lines , test again, etc... sub-divide problem down until find offending function call.