c programs

[jyoti das]

for the text file
lat long jan feb mar apr
-90 -180 -27.54 -39.22 -52.36 -57.00 -59.46 -60.23 -62.53 -62.82 -61.64 -52.15 -37.39 -27.83 -50.01
-90 -179 -27.53 -39.20 -52.33 -56.96 -59.43 -60.20 -62.50 -62.79 -61.61 -52.13 -37.38 -27.82 -49.99
-90 -178 -27.52 -39.19 -52.30 -56.92 -59.39 -60.16 -62.46 -62.76 -61.58 -52.10 -37.37 -27.82 -49.96
-90 -177 -27.51 -39.17 -52.27 -56.88 -59.36 -60.13 -62.43 -62.72 -61.54 -52.08 -37.35 -27.81 -49.94
-90 -176 -27.50 -39.15 -52.24 -56.84 -59.32 -60.09 -62.40 -62.69 -61.50 -52.05 -37.34 -27.80 -49.91
-90 -175 -27.50 -39.14 -52.21 -56.81 -59.28 -60.06 -62.36 -62.65 -61.46 -52.03 -37.33 -27.80 -49.89
-90 -174 -27.49 -39.12 -52.18 -56.77 -59.25 -60.02 -62.33 -62.62 -61.42 -52.00 -37.32 -27.79 -49.86
-90 -173 -27.49 -39.10 -52.15 -56.73 -59.21 -59.99 -62.29 -62.58 -61.38 -51.98 -37.31 -27.79 -49.83
-90 -172 -27.48 -39.09 -52.11 -56.69 -59.17 -59.95 -62.25 -62.55 -61.35 -51.95 -37.30 -27.78 -49.81
-90 -171 -27.48 -39.07 -52.08 -56.65 -59.14 -59.91 -62.22 -62.51 -61.31 -51.93 -37.29 -27.77 -49.78
-90 -170 -27.47 -39.05 -52.05 -56.61 -59.10 -59.87 -62.18 -62.48 -61.27 -51.90 -37.28 -27.77 -49.75
-90 -169 -27.46 -39.03 -52.02 -56.57 -59.07 -59.83 -62.14 -62.44 -61.23 -51.87 -37.27 -27.76 -49.72
-90 -168 -27.46 -39.01 -51.99 -56.53 -59.03 -59.80 -62.10 -62.40 -61.19 -51.85 -37.26 -27.75 -49.70
-90 -167 -27.45 -38.99 -51.96 -56.49 -59.00 -59.76 -62.07 -62.37 -61.15 -51.83 -37.25 -27.75 -49.67

[jyoti das]

Now i need to sum all these values within this range of lat and long, from jan to dec. please help me..........